Large and intensifying Hurricane Alex bears down on northeastern Mexico, South Texas

By: Dr. Jeff Masters , 2:23 PM GMT on June 30, 2010

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Hurricane Alex continues to intensify as it slowly bears down on the coast of northeastern Mexico. Brownsville long-range radar shows the spiral bands of Alex, which has dumped heavy rains of up to four inches in northeastern Mexico and near Brownsville, according to satellite estimates of rainfall. The Brownsville airport received 0.78" of rain in the hour ending at 8am CDT, and 0.61" in the hour ending at 9am CDT. Floods from Alex have already killed ten people--six in Nicaragua, and two each in El Salvador and Guatemala.


Figure 1. Snapshot of the Brownsville long-range radar showing Hurricane Alex approaching the coast.

The 7:12am CDT eye penetration of the Hurricane Hunters found a central pressure of 959 mb, a modest 2 mb drop from the reading four hours previous to that. They noted a very tiny eye, ten miles in diameter, with a gap in the northwest side. Tiny eyes like this tend to be unstable, and in the 9:05am CDT eye penetration, the Hurricane Hunters found that the inner eyewall had collapsed, and the pressure had risen 2 mb, to 961 mb. A new, much larger eye will form today as the day progresses. During these "eyewall replacement cycles", a hurricane will typically weaken a few millibars , and the strongest winds will spread out over a larger area as the hurricane conserves angular momentum. Thus, the hurricane still has about the same amount of destructive power, it is just spread out over a larger area. This tends to increase the hurricane's storm surge, but lessens the wind damage, since the extreme winds of the inner eyewall are no longer present. Satellite loops show a large, well-organized storm with increasing amounts of low-level spiral bands forming, and improving upper-level outflow. Data from last night's flight of the NOAA jet showed an unusually moist atmosphere surrounds Alex, so dry air is no longer a problem for it. It's a good thing Alex has less than a day before making landfall, or else is would be a large and very powerful major hurricane.


Figure 2. Visible light image of Tropical Storm Alex taken at 19:35 UTC (2:35 pm CDT) on June 29, 2010, by NASA's Aqua satellite. At the time, Alex was a tropical storm with 70 mph winds. Image credit: NASA.

Storm Surge
Traditionally, a storm's ranking on the Saffir-Simpson Scale--the familiar Category 1, 2, 3, 4, 5 rankings we always talk about--have also been used to quantify storm surge threat. However, large, weaker storms that cover a huge area of the Gulf of Mexico, like Alex, can generate a larger storm surge than a smaller but more intense hurricane with a higher Saffir-Simpson rating. Thus, the National Hurricane Center has formally discontinued use of the Saffir-Simpson scale to characterize storm surge, and is studying the possibility of issuing separate Storm Surge Warnings a few years from now. These would be in addition to their traditional Hurricane Warnings. To give us a better idea of a storm's surge potential, Dr. Mark Powell of NOAA's Hurricane Research Division has developed the Integrated Kinetic Energy scale to rank storms. The scale ranges from 0 to 6, and a parallel wind damage scale that runs from 0 to 6 is also generated. Alex had an Integrated Kinetic Energy of 2.6 on the 0 to 6 scale at 1:30pm CDT yesterday, and its destructive potential rating for winds was just 1.2. Thus, Alex's surge ranked alomst one-and-a-half categories higher in destructive potential than its wind. These numbers have probably increased by a full category since yesterday afternoon. NHC is giving a 40% - 60% chance of a storm surge of at least 3 feet affecting the Brownsville area, and 10% - 30% chance the surge will exceed 5 feet. In theory, a Category 2 hurricane moving WNW at 5 mph can bring a storm surge of up to 8 - 9 feet to the South Texas and northern Mexican coast.

Other Impacts
Alex is bringing bands of heavy rain to the coasts of Texas and Mexico, as seen on the Brownsville, Texas radar. Hurricane local statements with projections for how Alex will affect the coast are now being issued by the National Weather Service in Brownsville and Corpus Christi. Flooding damage from the expected 6 - 12 inches of rain from Alex will be the main concern. Wind damage is a lesser concern, since the core of Alex is making landfall in a swampy, sparsely populated region of Mexico. The combined wind, surge, and flooding damage from Alex may be similar to 2008's Hurricane Dolly, which hit near Brownsville. Dolly was a Category 2 hurricane offshore that weakened to a Category 1 hurricane with 85 mph winds when it made landfall, and did about $1 billion in damage. Dolly also generated two weak EF-0 tornadoes, and Alex is capable of generating a few tornadoes as well, according to the latest discussion from NOAA's Storm Prediction Center. The atmosphere is moderately unstable, there is plenty of moisture, and wind shear at low levels has been increasing this morning. The greatest threat for tornadoes will occur late this afternoon, on the right side of where the storm makes landfall.

Alex in historical context
Alex is the first June hurricane since Hurricane Allison of 1995. Allison briefly became a minimal 75 mph hurricane before weakening and hitting the Florida Panhandle as a tropical storm. Alex is the strongest June hurricane since Hurricane Bonnie of 1986, which had 85 mph winds. Bonnie was the first hurricane I flew into as a member of the Hurricane Hunters. Bonnie made landfall along the upper Texas coast, and caused less than $20 million in damage. If Alex strengthens to 90 mph winds, it will be the strongest June hurricane since Hurricane Alma of 1966, which had 125 mph winds as it skirted the Florida Keys. There have been only ten hurricanes in May or June since 1945; only four of these were major Category 3 or higher storms.

Track forecast for Alex
All of the models take Alex to the west or west-northwest into northern Mexico by early Thursday morning. However, the steering currents are fairly weak, and Alex could stall and move erratically at times today. I don't anticipate that this weakness in the steering currents will allow Alex to move northward and make landfall in Texas. After landfall, the ridge of high pressure forcing Alex westward should remain in place and strengthen, keeping Alex's remnants over northern Mexico for several days.

Intensity forecast for Alex
Alex is over a region of ocean with moderately high total ocean heat content . Wind shear has fallen to a low 5 knots, and is projected by the SHIPS model to remain in the low range, below 10 knots, through landfall. The combination of low wind shear, moderately high ocean heat content, and plenty of moisture should allow Alex to continue to intensify today. Alex's pressure is already characteristic of a Category 3 hurricane, but the storm is so large that it is taking time for the winds to catch up to the pressure falls. It is unlikely that Alex's winds will be at Category 3 strength at landfall, since the storm is undergoing an eyewall replacement cycle, and does not have time to build a tight inner eyewall with strong winds before landfall. A Category 2 storm at landfall looks more likely.

Elsewhere in the tropics
The latest run of the NOGAPS model predicts the formation of a tropical disturbance in the Western Caribbean on Monday. None of the other models is showing anything brewing over the coming seven days.

Wind and ocean current forecast for the BP oil disaster
Alex is generating very rough conditions over the Deepwater Horizon blowout location, with 6 - 8 foot waves and 3 - 4 foot swells. Strong southeast to south winds of 15 - 25 knots will blow over the oil slick region today through Thursday, according to the latest marine forecast from NOAA. The resulting currents will push oil to many protected bays and estuaries that haven't seen oil yet. In addition, the 1 - 2 foot storm surge Alex is generating along the Louisiana coast will act to push oil deep into some low-lying marshlands. While this oil will be diluted some by the wave action, the impact of the oil and accompanying toxic dispersants on the marshlands is of concern. The latest trajectory forecasts from NOAA and the State of Louisiana show oil will also move westward along the central Louisiana coast towards the Texas border. Winds will decrease to 10 - 15 knots Friday through Monday but remain out of the southeast, keeping the pressure on the regions of coast in Louisiana, Alabama, and Mississippi that are seeing oil hit their shores this week.

Resources for the BP oil disaster
Map of oil spill location from the NOAA Satellite Services Division
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

Next post
Either Rob Carver or myself will do an update late this afternoon or this evening.

Jeff Masters

Hurricane Alex (LRandyB)
Weather inbound to Hurricane Alex.
Hurricane Alex
Hurricane Alex (LRandyB)
Weather inbound to Hurricane Alex.
Hurricane Alex
Hurricane Alex (LRandyB)
Flight deck view from a WC-130J Hurricane Hunter aircraft
Hurricane Alex

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Patrap, looks like Madre Bay is going to get alot of storm surge looking at your sat pics
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Looking at the latest visible loop , Alex has the satelite presentation of a 115-125 mph CAT 3 hurricane in my opinion, I strongly suspect even though its close to making landfall , the NHC will upgrade Alex to the status it so rightly deserves!
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2596. centex
Quoting reedzone:
Alex will be making landfall around 8:30 p.m.
outer eyewall making landfall now. Moving very slow so take hour to cross.
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2595. leo305
Audrey a CAT 4 with 946mb in june, Alex 948mb a weak CAT 2 in june
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2594. marmark
Quoting CybrTeddy:


It is, Hurricane Allison in 1995 was the last time we have a Hurricane in June.
Thanks!!
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2593. Asta
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WoW! Big storm for June!!
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2591. Mikla
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2590. Patrap
Quoting CybrTeddy:
948 mb. Just three more MB's to beat Audrey's record.


I dont think the pressure reading from Alex is going to take any grief from the true Record of Audrey 53 years ago.

416 deaths.


Hurricane Audrey was the first major hurricane of the 1957 Atlantic hurricane season. Audrey was the only storm to reach Category 4 status in June. A powerful hurricane, Audrey caused catastrophic damage across eastern Texas and western Louisiana. It then affected the South Central United States as a powerful extratropical storm. The heaviest rainfall directly from Audrey fell near the Gulf coast, though heavy rainfall across the Midwest was caused by its moisture flowing towards a weather front to the north. In its wake, Audrey left $1 billion (2005 USD) in damage and 416 fatalities. At the time period, the devastation from Hurricane Audrey was the worst since the Great New England Hurricane of 1938.
Member Since: July 3, 2005 Posts: 420 Comments: 127536
Quoting reedzone:
Alex will be making landfall around 8:30 p.m.
I'm thinking 9PM EDT.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
2588. snotly
Quoting marmark:
OK, I admit it. I am lazy today. Someone told me this is the first hurricane to form in June in 15 years (Atlantic side). Doesn't seem right...


not right.
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2587. IKE
Barrier island may not be there much longer....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting bappit:

They might get tornadoes over land is what I heard. The circulation breaking down creates the eddies in which the tornadoes form. Don't want to fly through that. As I say, that's what I remember from somewhere.


Was half joking anyhow. I understand, and correct me if I'm wrong, there are established agreements regarding scientific missions especially for weather with regards to airspace. Besides commercial pilots would be violating airspace everytime a flight went from Miami to Mexico City. You are most likely correct; it's most likely a safety issue not a political one.
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Quoting CybrTeddy:
948 mb. Just three more MB's to beat Audrey's record.
Unless Recon goes in and takes another look we are stuck with 2nd place. But either way, Alex is the strongest June hurricane in the last 50 years.

3 more for the record, 2 more for the tie.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Alex will be making landfall around 8:30 p.m.
Member Since: July 1, 2008 Posts: 13 Comments: 7340
Quoting AstroHurricane001:
Let's take a look at a hurricane size comparison.

Emily, cat. 3:



Ike, cat. 2:



Alex, TS (outdated, I know):



So, given that Hurricane Ike was about the same size of Alex, had a higher central pressure at landfall, had about the same windspeed, and end up with a 22-ft maximum storm surge, the question is why is Alex expected to deliver what appears to only be a 5-ft maximum surge prediction in south Texas?


Ike was a larger and more powerful storm for a longer timeperiod, allowing his surge to build up to catastrophic levels.
Member Since: August 2, 2006 Posts: 46 Comments: 11665
948 mb. Just three more MB's to beat Audrey's record.
Member Since: July 8, 2005 Posts: 259 Comments: 23565
2580. Asta
Quoting TexasRGV:


What if it picked up a bus and tossed it through the roof? Would they cover that?

That story is hogwash.

I hope it truly is Hogwash...
But having been through Katrina
and seeing what my friends and family have been through with various agencies and companies...
it would not really surprise me...
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Quoting Clearwater1:
Any insurance agents care to field this question?
If a storm is labeled a "Tropical storm" when it hits your home, does your deductible fall under the category of simply wind damage? Conversely if it is labeled a "hurricane" will you be forced to use the "hurricane" deductible. Big cost difference. (at least in FL) The reason I ask, is because if what I mention is true, then it is very important in marginal storms as to how they are labeled coming inland. Anyone?


I'm not an agent, but I believe it may be tied to a "named storm," with respect to, if there's a "hurricane" deductible. I'm sure it varies in wording from state to state, but that's what I recall reading or hearing.
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Quoting bappit:

They might get tornadoes over land is what I heard. The circulation breaking down creates the eddies in which the tornadoes form. Don't want to fly through that. As I say, that's what I remember from somewhere.


I have seen something similar, they won't fly far over land due to turbulence.
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Quoting marmark:
OK, I admit it. I am lazy today. Someone told me this is the first hurricane to form in June in 15 years (Atlantic side). Doesn't seem right...


It is, Hurricane Allison in 1995 was the last time we have a Hurricane in June.
Member Since: July 8, 2005 Posts: 259 Comments: 23565
2576. centex
Outer eyewall approaching coast. Hope it just moves in and no bounce.
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948MB!

000
URNT12 KNHC 010002
VORTEX DATA MESSAGE AL012010
A. 30/23:40:40Z
B. 24 deg 20 min N
097 deg 17 min W
C. 850 mb 978 m
D. 82 kt
E. 351 deg 8 nm
F. 084 deg 107 kt
G. 351 deg 8 nm
H. 948 mb
I. 20 C / 1527 m
J. 22 C / 1522 m
K. 19 C / NA
L. OPEN SW
M. C10
N. 12345 / 8
O. 0.02 / 2 nm
P. AF304 1201A ALEX OB 26
MAX FL WIND 107 KT N QUAD 23:37:50Z
;


Member Since: September 2, 2009 Posts: 130 Comments: 21091
50 miles inland from Brownsville. We have had officially almost 2 inches more rain than Brownsville has had.

6.6 vs 4.7 as of 19:00
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BTW - forgive me if somebody has answered this... but if the pressure were to lower to below 944 by the next advisory, would it still count as June? it would be 1am July 1st zulu...

I know - random...
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2572. marmark
OK, I admit it. I am lazy today. Someone told me this is the first hurricane to form in June in 15 years (Atlantic side). Doesn't seem right...
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Quoting 1900hurricane:

He looks like he might be on the move again.


Alex went into a small retrograde loop, and is drifting W to SW again. Average motion over the past 140 minutes: SW. Looks like it has about four more hours over water.

Quoting CybrTeddy:


That translates to roughly what? 110 mph or so?


Possible cat. 3 by landfall? Yikes.
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Just a question about the last pass: Surface winds were significantly higher than flight level winds. When does that happen? Stadium effect?
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Wow, the eye looks to be hitting that opening/pass along the shoreline perfectly, not good!
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http://insurancenewsnet.com/article.aspx?id=198806&type=propertycasualty

long time lurker but thought this might help with the insurance question.

also: who is OZ and how do we view his crazyness?
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2567. bappit
Quoting LightningCharmer:
Mexican fighter jets to intercept a weather plane?

They might get tornadoes over land is what I heard. The circulation breaking down creates the eddies in which the tornadoes form. Don't want to fly through that. As I say, that's what I remember from somewhere.
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Member Since: July 8, 2005 Posts: 259 Comments: 23565
Quoting AlexEmmett:

Screw that theyll be to afraid to fly into a cane with a fighter jet


Can you make a more idiotic statement? Flying into another country's airspace without permission is an act of war technically.

*poof*
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2564. Asta
FZUS54 KCRP 302204
CWFCRP
COASTAL WATERS FORECAST
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
504 PM CDT WED JUN 30 2010
MIDDLE TEXAS COASTAL WATERS FROM BAFFIN BAY TO MATAGORDA SHIP CHANNEL
OUT TO 60 NAUTICAL MILES.
GMZ200-011100-
504 PM CDT WED JUN 30 2010

SYNOPSIS FOR THE MIDDLE TEXAS COASTAL WATERS
HURRICANE ALEX IS
EXPECTED TO MAKE LANDFALL THIS EVENING ALONG THE NORTHERN MEXICAN
COAST...AROUND 100 MILES TO THE SOUTH OF BROWNSVILLE. TROPICAL
STORM FORCE WINDS...VERY LARGE SEAS AND MULTIPLE RAIN BANDS AND
SQUALLS WILL IMPACT THE COASTAL WATERS TONIGHT. WINDS AND SEAS
WILL BEGIN TO DIMINISH BY THURSDAY MORNING AND CONTINUE THAT TREND
THROUGH THURSDAY NIGHT AS ALEX PUSHES DEEPER INTO MEXICO AND
WEAKENS. DEEP TROPICAL MOISTURE IN THE WAKE OF ALEX WILL CONTINUE
TO PROVIDE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH
THE JULY FOURTH WEEKEND.
GMZ235-011100-
BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O'CONNOR-
504 PM CDT WED JUN 30 2010

TORNADO WATCH 430 IN EFFECT UNTIL 8 PM CDT THIS EVENING

TROPICAL STORM WARNING IN EFFECT
LINK
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Your trusty update from Brownsville - averaging about 22mph from the east, but just after 6:30, got a few minutes with 31mph avg winds and a gust to 53.3.
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2562. centex
Many writing off low pressure and wind to size of system. Where is the history to support that and this system? Just crap to try and make this system not historical. Things have changed and I can read history.
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Quoting Asta:


!!??!!!??!?!!!!!
Are you serious?


What if it picked up a bus and tossed it through the roof? Would they cover that?

That story is hogwash.
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Quoting Patrap:
awesome
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2559. snotly
square eye. weird.
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I'm back. My browser totally crapped out on me. Maybe that was because I was running 56 tabs.....
Member Since: August 2, 2006 Posts: 46 Comments: 11665
Last post was an advisory behind due to a 2hour intermediary.

HurricaneAlex was^heading toward SanFernando,Tamaulipas,Mexico landfall in 2hours from NOW
(Straightline projection using its last 2 positions. Take with HUGE grain of salt)

Copy&paste TAM, MOB, PBI, SAL, 23.8N95.5W, 24.4N96.2W-28.7N88.4W, 24.5N96.8W-28.7N88.4W, 24.4N97.2W-28.7N88.4W, 24.5N96.8W-24.4N97.2W, 24.4N97.2W-24.2N97.8W into the GreatCircleMapper.

The shortest red line denotes the heading between the last two positions. Below the map shows:
H.Alex had a heading of 254.8degrees (~15degrees south of dueWest) while
traveling a distance of 26miles(~42kilometres) over 2hours at a speed of ~13mph(~21kph),
and was 40miles(~64kilometres) away from the coast in the direction of its heading.

^ EXTRAP or straightline projections are not forecasts of what will happen in the future,
especially not for TropicalCyclones. They merely aftcast what has already happened.
* DeepwaterHorizon is marked at 28.7N88.4W
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Quoting Patrap:


Just off of land, although that loop goes a bit back. Will probably make landfall at exactly 9:00 like Miami predicted.
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I'm sure Pat can tell you exactly, but when my brother flew recon in the 70's, they had a large tank inside beside the dropson guy that gave them 24hrs total fuel.
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2554. Patrap
Quoting JFLORIDA:


look at that pat - hexagonal symmetry in the eye


Natures a Pattern Gurl fo sho..

But ya knew dat JF.

Dats why We see alot alike.
Member Since: July 3, 2005 Posts: 420 Comments: 127536
2553. Asta
Quoting truecajun:


IDK answer to that one, but how crazy is this? my mom told me that her insurance company just recently sent out a letter that if there is oil in the water/hurricane damage on your home, then it won't be covered by flood insurance or wind and hail. so basically, any hurricane or hurricane related flood damage will not be covered in Louisiana. I forgot which company she said they are with, but it's a big "fancy" one. I told her she must have misunderstood, but she swears that's what it said.


!!??!!!??!?!!!!!
Are you serious?
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Quoting AlexEmmett:

Screw that theyll be to afraid to fly into a cane with a fighter jet
Mexican fighter jets to intercept a weather plane?
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2551. Patrap
Member Since: July 3, 2005 Posts: 420 Comments: 127536
eye on visible looks to be about to make landfall. how far off is alex?
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2548. Patrap
Member Since: July 3, 2005 Posts: 420 Comments: 127536

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.